Gas-carburetting apparatus



Dec. 28, 1954 R. A. PEDUzzl 2,698,226

GAS-CARBURETTING APPARATUS Filed April 24, 1951 lll/l ATTORNEY United States Patent O GAS-CARBURETTING APPARATUS Reynold A. Peduzzi, Trafford, Pa.

Application April 24, 1951, Serial No. 222,633

14 Claims. (Cl. 48-184) My invention relates to gas-carburetting apparatus for supplying a mixture of air and propane, natural gas, or other fuel-gas to the suction-intake of an internal-combustion engine or other combustion-device.

My present invention is an improvement over the gascarburetor of my Patent 2,209,206, granted July 23, 1940,

including such improved features as: a gas-pressure regulator which is capable of receiving compressed gas at pressures up to 150 pounds per square inch and delivering said gas, in as large quantities as may be required', at outletpressures of less than a pressure of 4 ounces per square inch over the prevailing atmospheric pressure; a gas-metering carburetor-valve, cooperating with a similar gas-metering valve in the regulator, for admitting progressively increasing rates of gas-flow, depending sensitively upon the amount of valve-opening; an opening-spring for balancing, or partially counteracting, my previously used closingspring, and operating on the carburetor-valve with an opening-force when the carburetor-valve is closed, the valve-opening spring-force becoming smaller when the carburetor-valve begins to open; and an auxiliary startingand-idling diaphragm, which co-operates with my previously used main carburetor-diaphragm by assisting in opening the carburetor-valve during starting and idling, and which provides a steady, preadjustable, idling-speed of the engine.

With the foregoing and other objects in view, my present invention consists in the combinations, systems, parts, and methods of design and operation, as hereinafter described and claimed, and illustrated in the accompanying drawing, wherein Figure 1 is a simplified and somewhat idealized diagrammatic vertical sectional view of an illustrative form of regulator-and-carburetor assembly embodying my invention, the section-plane through the carburetor being indicated approximately at I--I in Fig. 2, and

Fig. 2 is a larger-scale horizontal sectional View of the carburetor, on the section-plane indicated approximately at II--II in Fig. l.

As shown in Fig. l, my gas-carburetting apparatus comprises a gas-pressure regulator 3and a gas-carburetor 4, the latter delivering a gas-and-air mixture to the butterfly throttle-valve 5 which is adapted to `be connected to the suction-inlet of an engine (not shown).

The regulator 3 consists of a closed housing 6, having a high-pressure gas-inlet 7, a low-pressure gas-outlet 8, and a gas-metering regulator-valve 9. The valve 9 is movable from a position closing the high-pressure gasinlet 7, to various amounts of valve-openings. It has a long tapered conical shape, so that it admits progressively increasing rates of gas-flow, depending sensitively upon the amount of opening-movement of the valve.

For automatically and simply controlling the regulatorvalve 9, I provide a diaphragm 11, or other iiexibly mounted regulator-controlling pressure-plate, which separates the interior of the regulator from the external atmosphere. Usually, the diaphragm is protected externally by a dished cap or cover-plate 12, which is provided with a vent 13 for restrictedly venting the space Within the cover-plate 12 to the external atmosphere. The in-and-out movements of the diaphragm 11, in response to pressurevariations, are communicated to the regulator-valve 9 by a second-class lever 14, or other regulator-operating mechanical-connection means, preferably some form of motion-reducing mechanism resulting in greater forces on the valve 9 than the forces developed by the diaphragm 11. The etective pressure-area o f the diaphragm 11 is suf-y CTX ice

ciently large so that the valve 9 is closed when the internal pressure within the regulator is approximately that of the surrounding atmosphere. Preferably, the regulatorvalve 9 begins to open when the internal regulator-pressure falls below a critical pressure which is 4 ounces per square inch over the prevailing atmospheric pressure, or other slight amount in excess of the external atmospheric pressure.

The carburetor 4, as shown in Fig. l, comprises a venturi 15 having an air-inlet end 16 and a mixture-outlet end 17. Alongside of the venturi 15 is a gas-supply chamber which is provided by a dished plate 21 and a main carburetor-opening diaphragm 22, or other ilexibly mounted pressure-plate which separates the interior of the gas-supply chamber 20 from the external atmosphere. This diaphragm 22 is protected externally by a dished cap or coverplate 23, which is disposed over the external side of said diaphragm 22, so that the space within the cover-plate 23 constitutes an external chamber 24 for the diaphragm. This cover-plate 23 is provided with a vent 25 for restrictedly venting said external chamber 24 to the external atmosphere. The gas-supply chamber 20 is provided with a gas-supply connection 26 to a suction-point in the venturi 15, and preferably this connection to the venturi is t made at the point of maximum suction, which is just beyond the throat 27 of the venturi, or just after the inlowing air passes the point 27 of minimum cross-section in the venturi.f

Disposed at the center of the dished plate 21 of the gassupply chamber 20, as shown in Fig. 2, is a gas-inlet chamber 30, Which is provided by means of a bore 30 in a casting 31, said bore being at right angles to the main carburetor-closing diaphragm 22. At one end, the gas-inlet bore 30 is provided with a gas-outlet 32 to the gas-supply charnber 20. Disposed within this gas-inlet bore 30 is a gasmetering carburetor-valve 33 which co-operates with thev gas-outlet 32. This valve 33 has a valve-stem 34 which extends into the gas-supply chamber 20, where it is fastened to the center of the main carburetor-opening diaphragm 22 as shown at 35. The other end of the gas-inlet lbore 30 is shown as being provided with a short threaded tubular extension 36, which is closed, in turn, by a removable cap 37. Disposed within the gas-inlet bore 30, back of the carburetor-valve 33, is a closing-spring 38, which is compressed by an adjustable nut 39 Within the threaded tubular extension 36, preferably having self-locking,

threads. Threaded through this nut 39 is a maximumopening abutment-rod 40 which provides an adjustable maximum-opening distance 41 through which the carburetor-valve may be opened by the main diaphragm 22, as will be subsequently described.

As shown in Fig. 2, the casting 31, which has the gasinlet chamber or bore 30 therein, is provided with a lateral communicating-opening 43 which serves as a gas-inlet,

being connected to the regulator-outlet 8 (Fig. l) by means of a low-pressure gas-pipe 44.

In accordance with my present lnventlon, as shown in Fig. 2, I also provide the outer cover-plate 23 of the main v carburetor-opening diaphragm 22 with a centrally disposed, outwardly projecting, pipe-extension 45, withinY which is disposed a carburetor-Valve opening-spring 46 which is compressed between the outer face of the main diaphragm 22 and an adjusting nut 47 which is threaded within the pipe-extension 45. The opening-spring 46 s centered on an outward valve-stem extension 34', which constitutes, in effect, a continuation of the valve-stem 34. The valve-stem extension 34 extends all the way through a guide-hole 48 in the adjusting nut 47, so that it has a sliding motion within said hole 48 as the main diaphragm A 22 moves in and out, in response to pressure-changes.

In accordance with my present lnventlon, as further shown in Fig. 2, I provide the outer end of the pipe-extension with a short threaded tubular extension 49 which is secured to, and opens into, an auxiliary suction-chamber 50, which is usually smaller than the gas-supply chamber 20, and which is similarly provided by a dished plate 51 and a suction-chamber diaphragm 52, or other tlexibly mounted pressure-plate which separates the interior of the suction-chamber from the external atmosphere. diaphragm 52 is protected externally by a dished cap or cover-plate 53, which may be provided with a vent 55 for Patented Dec. 28, 1954.

This

restrictedly'ventingthe space within the cap 53 to the externalatmosphere.

The auxiliary suction-chamber 50 is provided with a suction-connection, in the fornrof a suction-pipe 57, which extends-fromthe suction-'chamber 50 to'somepart ofthey mixture-outlet portion 17 of the venturi 15, preferably to theengine-side 58 of theV throttle-valve 5,'as-shownl in` Fig; 1.

The suction-chamber diaphragm 52 is mounted-at its center, onl an intermediate part of a diaphragm-stem-i, the inner end'of which isy normally (when the engine 'is-not running) spaced from the valve-stem extension 34', as shown at-65 in Fig.v 2. The suction-chamber diaphragm 52-is preferably biasedoutwardly, away from the valvestem extension-34, by means'of a spring'66, which abuts against an adjusting nut 67 which is`threaded withinthe tubular extension 49. This adjusting-nut-l is providedwith aV guide-hole 68, for slidably guiding the inwardly extending-portion ofl the diaphragm-stem 64, as shown in' Fig.- 2. Whenthe suction-chamber diaphragm 52 is drawn inwardly, by a sub-atmospheric pressure in' the suctionchamber 50, as -willbe subsequently described, the-inwardly extending portion of the diaphragm-stem 64`will close-the space 65 and comeinto engagement with the valve-stem extension 34', so thatthc suction-chamber-diaphragm-stern 64 thus acts as an idling-assisting mechanicalconnection means, between the suction-chamber diaphragm 52 and the ,carburetor-valve33,'fory assisting the main carburetor-opening diaphragm 22 in opening :the carburetor-valve -33 during the starting andthe-idling of the engine-(not shown), asiwill be subsequentlyv described.

Means should be provided for limiting the inward movementy of the suction-chamber diaphragm 52. in Fig. 2, the-means to-this`end is' a centrally disposed,'outwardly projecting, guide-sleeve 69 which is secured to a central holein the' suction-chamber cover-plate 53. The outwardly extending part of the diaphragm-stem 64 extends slidably all the way through this guide-sleeve69, and is provided, on its-end, with an idling-adjustment nut 71, which-is backed by a lock-nut 72. In thenormal (no-suction) position of the suction-chamber diaphragm-stem 64, there` is` thus a certain end-spacing "i3 between the adjustment-nut 71-and the end ofthe guide-sleeve 69, which may be adjusted to regulate the amount of suction-chamber valve-opening of the carburetor-valve 33to a small fixed amount suitable for the'idling-operation of the engine (not shown).

Inoperation,` when" the engine (not shown), whiohisV connected tof'the-discharge-end SS'of-the throttle-valveS in- Figi l, is not running, the carburetorvalve-33 (FigfZ) is closed tightly, so that no gas-can' flowV therethrough; When the-high-pressure gas-iis rst supplied to the-regulater-inlet 7, the regulator-diaphragm'11-automatically opens=once,-very quickly and very slightly, to' admit-aftiny amount of gas, just enough sothat the internalregulator-vv pressure reaches the small'pressure-differential,over the ambient atmospheric pressure, which is necessary to 'comL pletely close the regulator-valve'Q. Under these-staticy conditions, the closedcarburetor-valve 33 (Fig-2) holds f thi's very slight critical pressure within the regulator 3, and no gas will ow continuously through either the-regu'- lator-valve 9-(Fig. 1) or the carburetor-valve-33 {Figg-Z).

When-fthe engine* (not shown) isrotateduduringthe starting-operation, the throttle S'should beleft closed, unless aA choke-valve (not shown) is used-in the air-in-l take 16. Under thesc-conditions-,the rot-atingengine", previous to itspstarting, develops a suction at the'y engine-end 58 of the closedthrottle-valve 5, and thus suction-s corn'- municated, by the suction-pipe 57, to the suction-chamber S`(VFig.-2v), which draws in the suction-chamber diaphragm 52 tothe full amount permitted by thej-idling-.ad justlnentspacing 73 ofthe adjusting-nut 71fon-thev outer end of the diaphragm-stem 64; This provides-asmall-and1 constant` idling-adjustment,or slight opening of=the'c:ar-y buretor-valve 33, thus permitting gas to flow,-at1 a-constant slow" rate, through the 'carburetor-valve 33,--'andthenthrough the gas-supply chamber 20, the gas-supply'connection 26, the venturi mixture-outlet 17, andthe closed throttle-valve 5, to the engine (not shown) Whieh'is connected at 58 I(Fig. l).

As l soon as the carburetor-valve v33 opens,- thefsuctions, of both the engine-and the venturi are communicated; through thelow-pressure gas-pipe 44, to the regulator ,3, dropping the internal regulator-pressure belowthe -cr-iticaly pressure which holds the regulator-valve 9 closed, Thus,.-

. be much smaller.

4. the regulator-valve opens by whatever amount is needed to-supply^the rate of' gas-ow which is called for by'the amount of valve-opening of the carburetor-valve 33.

During the idling-operation, the suctions of both the engine and the venturi 15 are communicated, through the gas-supply connection 26, to the gas-supply chamber 20, thus drawing the main carburetor-opening diaphragm 22 inwardly, thus developingia force which tends to open the carburetor-valve 33 against the bias of its closing-spring 38. This action, by'itself, however, that is, without the aid of my auxiliary suction-chamber 50, has proved to be not very smoothorV constant, so that itis much preferable to make the adjustment-suchthat the main diaphragm 2.2, during idling, is not quite able, alone, to cause the required idling-opening of the carburetor-valve 33, so that the auxiliary suction-chamber diaphragm S2 controls the idling-opening of the carburetor-valve 33 by holding it xed at the amount which is set by the idling-adjustment spacing -73.

During'the idling-operation also, the auxiliary suctionchamber 50 is restrictedly vented into the external chamber 24 of the main carburetor-diaphragm 22, through Athe small clearances between the bore 63 and the pin 64, and between 'the bore48fand the pin 34. These clearances are shown-exaggerated, in Fig. 2, for clearness of illustration,'but lthey are`preferabiy small enough so that air isf'slowly'sucked therethrough, bythe auxiliary suctionchamberQthus 4somewhat reducing the valve-opening pressure oflthe main-diaphragm 22 during the idling ol the engine. Thishelps to prevent the main diaphragm 22 fromopening the carburetor-valve 33 any wider than is provided for bythe idling-setting 73 of the suction-chamber diaphragm 52, during idling. At the same time, the external chamber 24t'of the Vmain diaphragm 22 is restrictedly vented tothe outside atmosphere by the vent 25, which thus tends to'bring the pressurein said external chamber 24 up close to the prevailing atmospheric pressure.

When-the engine (not shown) is rst being started, the initial 'opening-movement of the carburetor-valve 33 Ais a'ssisted'by the' opening-spring 46, which partially counteracts the-closing-spring 38 by exerting a valveopening"spr'ingiforce whichY is strongest when the valve 33 is closed, and which quickly becomes smaller when said-valve-beginsftoopen.v This makes it easier for theHsuction-chamber diaphragrrr52,wthy the aid of the diaphragm- 22on the gas-supply chamber, to open the carburetor-valve'33 and admitsome gas to the engine when the engine is being started.

Whenthe'enginepassesits idling stage, andbegins to carry a-usefulload, with-the carburetor valve 33 opened-more widely,'the pressure of the opening-spring 46 will preferably fall off to nothing, or at least it will This yisdesirable because, under these running-conditions,the engine exerts a suiciently strong suction on A'thecarburetor to give the main diaphragm 22 adequate control over the carburetor-valve'33, the effectivefpressure-*area of -said main daphragm 22 being .sufficiently-large so that the ycarburetor-valve 33 will begin toppen, and remain open, in response to a reason'- ablyf small suction in the gas-supply chamber 20.' In this way, the engine 'gets as much gas as itV may need, dependinguponfthe amount of opening-of thethrottlevalve' 5. I have=found that the jointuse of an openingspring 46; as well as a Vclosing-spring38, makes it much easier to obtain ythe proper control over the carburetorvalve 33.

When the engine is` running under load, thethrottle 5 'isalways-open, sothat theiengine-suction onthe suction-pipe 57-isver'y much reduced, so much so 'that the suctton-chamber'-diaphragm 52 is practically p'ut`out ofy commission, and the` carburetor-valve 33 is` then underthe-Tsole control of the main diaphragm l22.

TheY` carburetor-valve 33,1 like' the regulator-valve '9, hasla long,taperfed,\conical shape, so that'ithas' agasmetering action, admitting progressively' increasingrat'es of-g'as-ow, depending sensitively uponthe amount-of opening-movement of' the carburetor-valve 33. When the enginey isioperating under load, these two gas-meter- 1ngvalves` 33 andY 9 thus operate smoothly together, the' carburetor-valvev 33 determining' the rate of gas-ow into the-engine, while the regulator-valve 9 opens by whatever-amount-is-necessary to` hold the internal f gaspressure ini-the regulator 3 ata fairly constant' lowpressure value-which is somewhere around` atmospheric' pressure, varying from a maximum pressure which is preferably only a few ounces per square inch higher than atmospheric pressure, and ranging, at full throttle,

to a minimum pressure which is preferably only a few ounces per square inch lower than atmospheric pressure. Thus the gas-delivery pressure, to the carburetor, remains approximately constant, at about the atmospheric pressure, whatever may be the gas-flow requirements. This combination of the two gas-metering valves 9 and 33 thus results in an extremely smooth engine-performance.

The vents or breather-openings 13, 25 and 55, for the spaces on the outer sides of the various diaphragms 11, 22 and 52, also provide a means for adjusting the performances of the associated diaphragms, principally operating as damping-means for preventing pumping or overshooting of the respective diaphragms. Thus, when a sudden pressure-drop occurs on the inner face of any diaphragm, the diaphragm moves inwardly and creates a slight restraining-suction on its outer face, because the vent does not admit air fast enough to maintain atmospheric pressure on the outer face of the diaphragm at the instant when the diaphragm suddenly moves inwardly. A similar damping-effect is exerted by the vent, when its associated diaphragm suddenly moves outwardly. In this way, each diaphragm begins to slow down as it approaches its final position in response to any sudden pressure-change, thus preventing overshooting, and contributing to smooth engine-performance. The vents 13, 25 and 55 are adjustable, so that their damping-actions may be properly predetermined.

The vent 55, which is associated with the auxiliary suction-chamber diaphragm 52, is in parallel with the clearance-space which is provided between the bore of the guide-sleeve 69 and the pin 64, this clearance-space being exaggeratedly shown in Fig. 2, as explained in connection with the bores 68 and 48. Sometimes, this clearance-space Within the guide-sleeve 69 may provide all the venting which is necessary for the outer face of the auxiliary idling-controlling diaphragm 52, in which case the associated vent 55 may be omitted.

While I have shown my invention in but a single illustrative form of embodiment, I wish it to be understood that considerable modifications may be made, by way of substitution of equivalents, or by the addition or omission of various parts or refinements, or by changes in the relative positions, sizes or adjustments of the various parts, without departing from the essential spirit of the invention. I desire, therefore, that the appended claims shall be accorded the broadest construction consistent with their language.

I claim as my invention:

1. In a gas-carburetting apparatus for supplying a gas-and-air mixture to an engine, the combination including: a gas-pressure regulator having a high-pressure gas-inlet, a low-pressure gas-outlet in communication with the internal pressure within the regulator, a gas-metering regulator-valve which is movable, from a position closing said high-pressure gas-inlet, to various amounts of valveopenings, for admitting progressively increasing rates of gas-flow depending sensitively upon the amount of opening-movement of the regulator-valve, a flexibly mounted regulator-controlling pressure-plate, separating the interior of the regulator from the external atmosphere, and a regulator-operating mechanical-connection means, between said regulator-controlling pressure-plate and the regulator-valve, for closing the regulator-valve in response to a predetermined critical outlet pressure of the regulator, the effective pressure-area of the regulator-controlling pressure-plate being sufficiently large so that the regulator-valve is closed when the outlet pres-I sure of the regulator is approximately that of the surrounding atmosphere; and a gas-carburetor comprising a venturi having an air-inlet end and a mixture-outlet end, a gas-supply chamber, a gas-supply connection between the gas-supply chamber and a suction-point in the venturi, a gas-inlet chamber connected to the regulatoroutlet, a gas-outlet from said gas-inlet chamber to said gas-supply chamber, a gas-metering carburetor-valve which is movable, from a position closing said inletchamber outlet, to various amounts of valve-openings, for admitting progressively increasing rates of gasflow depending sensitively upon the amount of openingmovement of the carburetor-valve, carburetor-valve closing-means for yieldably biasing said carburetor-valve toward its closed position, means for limiting the maximum fio y opening-movement of the carburetor-valve, a flexibly' mounted carburetor-controlling pressure-plate, separating the interior of the gas-supply chamber from the exthe critical output regulator-pressure, below which the regulator-valve begins to open, being slightly above the external atmospheric pressure, whereby, when the carburetting apparatus is not delivering any gas-and-air mix- .f

ture to the engine, the closed carburetor-valve enables the regulator to maintain said critical output regulator-pressure therein.

3. The invention as defined in claim l, characterized by the regulator-operating mechanical-connection means including a motion-reducing mechanism resulting in greater forces on the regulator-valve than the forces developed by the regulator-controlling pressure-plate.

4. The invention as defined in claim l, characterized by the regulator-operating mechanical-connection means including a second-class lever.

5. The invention as defined in claim 1, in combination with a carburetor-valve opening-spring, mounted so asto exert an opening-force on the carburetor-valve when y the carburetor-valve is closed, the valve-opening spring- .i force becoming smaller when the carburetor-valve begins to open.

6. The invention as defined in claim l, in combination with a carburetor-part for providing an auxiliary suctionchamber, a suction-connection between the mixture-outlet portion of the carburetor and said auxiliary suctionchamber, a flexibly mounted suction-chamber pressureplate separating the interior of the auxiliary suctionv chamber from the external atmosphere, an idling-assisting .1 mechanical-connection means, between said suction-chamber pressure-plate and the carburetor-valve, for causing a small opening of the carburetor-valve in response to a suction within said auxiliary suction-chamber, and idlingcontrolling means for limiting the valve-opening movement of said idling-assisting mechanical-connection means,I

7. The invention as defined in claim 6, characterized by a cover-plate over the external side of the carburetorcontrolling pressure-plate to form an external chamber therefor, means for restrictedly venting said external chamber to the external atmosphere, and means for .restrictedly venting the auxiliary suction-chamber to said external chamber.

8. The invention as defined in claim 1, in combination with an engine-throttle valve on the mixture-outlet end of the venturi, a carburetor-part for providing an auxiliary suction-chamber, a suction-connection between the engineside of said throttle valve and said auxiliary suctionchamber, a flexibly mounted suction-chamber pressureplate separating the interior of the auxiliary suctionchamber from the external atmosphere, an idling-assisting mechanical-connection means, between said suction-chamber pressure-plate and the carburetor-valve, for causing a small opening of the carburetor-valve in response to a suction within said auxiliary suction-chamber, and idlingcontrolling means for limiting the valve-opening movement of said idling-assisting mechanical-connection means.

9. The invention as defined in claim 8, characterized by a cover-plate over the external side of the carburetorcontrolling pressure-plate to form au external chamber therefor, means for restrictedly venting said external chamber to the external atmosphere, and means for restrictedly venting the auxiliary suction-chamber to said external chamber.

l0. A gas-carburetor comprising a venturi having an air-inlet end and a mixture-outlet end, a gas-supply chamber, a gas-supply connection between the gas-supply chamber and a suction-point in the venturi, a gas-inlet chamber having a gas-inlet, a gas-outlet from said gas-inlet chamber to said gas-supply chamber, a gas-metering carburetorvalve which is movable, from a position closing said inlet-chamber outlet, to various amounts of valve-openings, for admitting progressively increasing rates of gasfiow depending sensitively upon the amount of openingmounted tcarburetor-controlling pressure-plate, separating' the interior: cf'thevgas-supply chamber from the external atmosphere, a carburetor-operating mechanical-connecnon means',-bet\veenvv said carburetor-controlling pressureplate and the 'carburetor-valve, for causing agas-metering opening'of-said carburetor-valve in response to a suction withinnsaidt4 gassupply chamber, the eiective pressurearea of the carburetor-controllingpressure-plate being suiiiciently large so that'the carburetor-valve will begin tol open in response to a reasonably small suction in the gas-supply chamber, and ai carburetor-valve openingspring .mounted so as -to exert anopening-force on the carburetor-valve when the carburetor-valve begins to open.

ll. A gas-carburetor comprising a venturi having an air-lift'end and a' mixture-outlet end, a gas-supply chamber, a gas-supply connection between the gas-supply chamber and a suction-point" in the venturi, a gas-inlet chamber having'a gas-inlet, a gas-outlet from said gas-inlet chamber to said gas-supply chamber, a gas-metering carburetor-valve whichisV movable, from a position closing said inlet-chamber outlet, tovarious amounts of valveopenings, for' admitting progressively increasing rates of gas-iiow depending sensitively upon the amount of opening-movement of the carburetor-valve, carburetorvalve closing-means for yieldably biasing said carburetorvalvetowa'rd its" closed position, means for limiting the maximum opening-movement of the carburetor-valve,` a iiexibly mounted carburetor-controlling pressure-plate, separating the' interior of the gas-supply chamber from the external atmosphere, a carburetor-operating mechanical-connection means, between said carburetor-controlling pressure-plate and the carburetor-valve, for causing a gasmeteringk opening of said carburetor-valve in response to a-sucti`on within said gas-supply chamber, the eective pressure-area ofthe carburetor-controlling pressure-plate being suiiiciently large so that the carburetor-valve will begin to open in response to a reasonably smallsuction in megas-supply chamber, an auxiliary suction-chamber, asuction-connectionV between the mixture-outlet portion ofthe carburetor and said auxiliary suction-chamber, a exiblyimounted suction-chamber pressure plate separatin'g'the interior of the auxiliary suction-chamber from thc externalfatmosphere, an idling-assisting mechanicalconnection. means, between said suction-chamber pressure-plate and the carburetor-valve, for causing a small opening of the carburetor-valve in response to a suction within said auxiliary suction-chamber, and idling-controlling means for limiting the valve-opening movement ot said` idling assistingl mechanical-connection means.

l2. The invention as defined in claim 1l, characterized by cover-plate over the external side of the carburetorcontrolling pressure-plate to form an external chamber therefor, meansv for restrictedly venting said external chamber to the externalatmosphere, and means for restrictedly venting the auxiliary suction-chamber to said external chamber.

and-air lmixturel to fan'engine, the'combinatlon including? a" gas-carburetor comprising. a venturi having' an air-inlet end- 'anda mixture-outlet end, a gas-supply'ch'amber," a'

gas-supply' connectionbetween the: gas-supply chamber and; a suction-point in the venturifa gas-inletchamber' tween' said carburetor-controllingl pressure-plate' andthe' carburetor-valve, for causing a gas-metering'opening'ofl said carburetor-valve'in response'to a suction within 'said gas-supply chamber, the effective pressure-'area offthe carburetor-controlling pressure-plate being su'iiici'ently large so 'that the carburetor-valve will'begin to"open"'in response to a reasonably'small suction inithej gas-supply chamber, anlengine-throttle valve on the mixture`=ontlet end :of the venturi, acarburetor-part 'for providing an auxiliary suction-chamber, a suction-connection 'between the engine-side of said throttle valve and' said auxiliarysuc tion-chamber, aj flexibly mounted suction-chamber pres sure-plate separating theI `interior of the auxiliary "suctionchamber from the external atmosphere, an idlingass'ist-, ing 'mechanical-connection means, between said suction-l chamber pressure-plate andfr the carburetor-valve, for causing' a small opening" of the carburetor-valve in respense to suction within said lauxiliary suction-chamber,"

and' idling-controlling'.means fo'limiting .the valve-opening movement of -said idling-'assisting mechanical-connection means. g y

l4`. The invention as defined'. in claim '13, characterized by cover-plateover the external side of the 4carburetorcontrolling' pressure-plate to form an external chamberV therefor, means for restrictedly venting said' external chamber to 'thefexternal atmosphere;v and means for restrietedly venting the auxiliary suction-chamber' to said external'chainb'er';

References Citediin the iile of this patent UNITED STATES PATENTS Number Name Date l Re; `13,631 Park Oct. 21, 1913 227,234 Foster ,May 4; v1880V 744,679 Cook Nov. 17, 119,03 2,073,299 Ensign Mar. 9, 19,37l 2,203,961 Jonesv .Tune "Il, 1940 2,244,111 McKee June 3,l 1941 

13. IN GAS-CARBURETTING APPARATUS FOR SUPPLYING A GASAND-AIR MIXTURE TO AN ENGINE, THE COMBINATION INCLUDING: A GAS-CARBURETOR COMPRISING A VENTURI AN AIR-INLET END AND A MIXTURE-OUTLET END, A GAS-SUPPLY CHAMBER, A GAS-SUPPLY CONNECTION BETWEEN THE GAS-SUPPLY CHAMBER AND A SUCTION-POINT IN THE VENTURI, A GAS-INLET CHAMBER HAVING A GAS-INLET, A GAS-OUTLET FROM SAID GAS-INLET CHAMBER TO SAID GAS-SUPPLY CHAMBER, A GAS-METERING CARBURETORVALVE WHICH IS MOVABLE, FROM A POSITION CLOSING SAID INLETCHAMBER OUTLET, TO VARIOUS AMOUNTS OF VALVE-OPENINGS, FOR ADMITTING PROGRESSIVELY INCREASING RATES OF GAS-FLOW DEPENDING SENSITIVELY UPON THE AMOUNT OF OPENING-MOVEMENT OF THE CARBURETOR-VALVE CARBURETOR-VALVE TOWARD ITS FOR YIELDABLY BASING SAID CARBURETOR-VALVE CLOSING-MEANS CLOSED POSITION, MEANS FOR LIMITING THE MAXIMUM OPENINGMOVEMENT OF THE CARBURETOR-VALVE, A FLEXIBLY MOUNTED CARBURETOR-CONTROLLING PRESSURE-PLATE, SEPARATING THE INTERIOR OF THE GAS-SUPPLY CHAMBER FROM THE EXTERNAL ATMOSPHERE, A CARBURETOR-OPERATING MECHANICAL-CONNECTION MEANS, BETWEEN SAID CARBURETOR-CONTROLLING PRESSURE-PLATE AND THE CARBURETOR-VALVE, FOR CAUSING A GAS-METERING OPENING OF SAID CARBURETOR-VALVE IN RESPONSE TO A SUCTION WITHIN SAID GAS-SUPPLY CHAMBER, THE EFFECTIVE PRESSURE-AREA OF THE CARBURETOR-CONTROLLING PRESSURE- PLATE BEING SUFFICIENTLY LARGE SO THAT THE CARBURETOR-VALVE ON THE MIXTURE-OUTLET RESPONSE TO A REASONABLY SMALL SUCTION IN THE MIXTURE-OUTLET CHAMBER, AN ENGINE-THROTTLE VALVE ON THE MIXTURE-OUTLET END OF THE VENTURI, A CARBURETOR-PART FOR PROVIDING AN AUXILIARY SUCTION-CHAMBER, A SUCTION-CONNECTION BETWEEN THE ENGINE-SIDE OF SAID THROTTLE VALVE AND SAID AUXILIARY SUCTION-CHAMBER, A FLEXIABLY MOUNTED SUCTION-CHAMBER PRESSURE-PLATE SEPARATING THE INTERIOR OF THE AUXILIARY SUCTIONCHAMBER FROM THE EXTERNAL ATMOSPHERE, AN ILDING-ASSISTING MECHANICAL-CONNECTION MEANS, BETWEEN SAID SUCTIONCHAMBER PRESSURE-PLATE AND THE CARBURETOR-VALVE,FOR CAUSING A SMALL OPENING OF THE CARBURETOR-VALVE IN RESPONSE TO A SUCTION WITHIN SAID AUXILIARY SUCTION-CHAMBER AND IDLING-CONTROLLING MEANS FOR LIMITING THE VALVE-OPENING MOVEMENT OF SAID IDLING-ASSISTING MECHANICAL-CONNECTION MEANS. 